The t-distribution table is a table that shows the critical values of the t distribution. To use the t-distribution table, you only need to know three values: The degrees of freedom of the t-test The number of tails of the t-test (one-tailed or two-tailed) The alpha level of the t-test (common choices are 0.01, 0.05, and 0.10) It can be significantly smaller, but you weren't asking that question. That would be a one-tailed test. For a two-tailed test if the calculated value of t exceeds the tabled value, then report the p value in the table. For a one-tailed test, the p value is divided by two. So 'p . 0.05' becomes 'p 0.025." This t-distribution table provides the critical t-values for both one-tailed and two-tailed t-tests, and confidence intervals. Learn how to use this t-table with the information, examples, and illustrations below the table. The statistical tables for t and for Z provide critical values for both one- and two-tailed tests. That is, they provide the critical values that cut off an entire region at one or the other end of the sampling distribution as well as the critical values that cut off the regions (of half the size) at both ends of the sampling distribution. Critical Value Calculator. Use this calculator for critical values to easily convert a significance level to its corresponding Z value, T score, F-score, or Chi-square value. Outputs the critical region as well. The tool supports one-tailed and two-tailed significance tests / probability values. In one tailed t-tests, the critical value of t from t-distribution table represents the rejection area of distribution either left or right of the mean. In single tailed t-test, the critical value of t at a specified level of significance (α) is calculated either left side or right side of the mean of t-distribution. The function gives the critical value of t for the one-tailed test. If you want the critical value of t for a two-tailed test, divide the significance level by two. Example: Calculating the critical value of t in R To calculate the critical value of t for a two-tailed test with df = 29 and α = .05: 3SRn.

one tailed critical value table